1. Technical Field
The present invention relates to an electrochemical strip, and more particularly to an electrochemical strip for bio-test.
2. Description of Related Art
The development of the mechanical and electrical technology facilitates detection of biological samples via electrochemical or optical methods. By employing electrochemical method, for example, blood sugar can be detected via redox reaction that occurs when glucose in blood sample reacts with glucose oxidase (GOD) coated on the test strip. Specifically, an electric signal produced by redox reaction is used to detect the content of glucose participated in the response, and the signal can be converted to the concentration of blood sugar. By employing optical method, a reaction occurred between glucose and enzyme results in changing of color in test strip, then the change of color is detected and converted to concentration of blood sugar via colorimetric method.
Recently, an electrochemical strip is employed increasingly. Since the strip needs to detect an electric current signal produced by the electrochemical reaction, the strip needs to have a conductive electrode to receive the signal and transmit the signal to a measuring instrument for conversion. According to the techniques well known to those skilled in the art, the conductive electrode is usually made by plating nickel (Ni) and palladium (Pd) on a copper electrode or coating active-carbon layer on a silver paste. However, the general cost of electro-deposing nickel and palladium on a copper electrode is high. On the other hand, there is a method to form the electrode by directly disposing an inert group metal such as gold, platinum, and palladium on a substrate via vapor-deposition or sputtering-deposition, and then eliminating the unnecessary part via etching to keep the necessary parts only. However, this method results in serious material consumption and high manufacturing cost. Additionally, one may manufacture the electrode by coating an active-carbon layer on printed silver paste circuits to reduce the cost. Nevertheless, the manufactured electrodes have worse accuracy and stability in measurement than the electrodes made via the vapor-deposition or sputtering-deposition and which will consumes extra cost in quality control.